The present invention relates to a process for oxidizing diethylbenzenes, and more particularly, it relates to a process for oxidizing diethylbenzenes with a molecular oxygen-containing gas without previously removing impurities from the diethylbenzene feedstock.
In view of the greatly increased demand for styrene in the past few years, there has resulted a concomitant increase in the availability of diethylbenzenes. It is already known to oxidize these diethylbenzenes to produce diethylbenzene hydroperoxide, which is useful in its own right as a free radical initiator and the like and, more importantly, is useful as an intermediate for the production of other compounds such as ethylphenols which find valuable utility in the preparation of additives for lubricating oils and as stabilizers for rubber, synthetic resins, oils, etc. In addition, the decrease in the supply of cresols has resulted in an increasing demand for substitutes such as ethylphenols.
The oxidation of diethylbenzenes to produce diethylbenzene hydroperoxide has been carried out by passing a molecular oxygen-containing gas through a diethylbenzene feedstock at a temperature generally between about 100.degree. and 170.degree. C. and at a pressure less than about 10 atmospheres, and generally at about atmospheric pressure. It has been observed in carrying out such a reaction that the selectivity in hydroperoxide is very poor if the diethylbenzene being treated is not of high purity. In particular, it has been found that the diethylbenzene must be free from the heavies and the color-bodies which generally are present in conventional diethylbenzene feedstocks, especially acids and arylvinyl compounds. Accordingly, it has been found necessary to purify the diethylbenzene feedstock in every instance before the same is subjected to oxidizing conditions in order to maintain an acceptable degree of selectivity for the hydroperoxide. This purification has in the past been carried out by passing the diethylbenzene feedstock through a pre-distillation step, followed preferably by an absorption step with silica gel or the like, prior to contacting the feedstock with the molecular oxygen-containing gas.